Radio interference eliminator



I May 31, 1927. F w STEIN RADIO INTERFERENCE ELIMINATOR 7 Filed AnriI SO. 1925 7 ing set.

i in

. antenna circuit andcomprises an absorption Patented May 31, 1927.

FRED WI IJIAMT STEIN,

RA mo INTERFERENCE ,nLI yrInAToa.

Application ieaapril 30, 1925. sei'ia1No. 27,1 18.

This invention relates to devices for pei sired stations and also to a noticeable extent reducing theinterference caused by dis: charges of static electricity into the IQCBlV To that end the invention "contemplates as its primary object the provision of a simple,practi cal and reliable device having novel features of construction which; en-

hance its value from a manufacturing standpoint and also facilitates its installation and manipulation. v I p r Another object of the invention is to provide a device which may be'inc luded inthe circuit for extracting the interfering oscillations from the antenna circuit, thus effectually dampening the undesirable OSCll lations therein. a

'AJ-further object ofthe invention is to provide a device of the character set forth which maybe used in connection with any type of radio receivingapparatus. I. ..With the above and other objectsin view which will more readily appear as the natureof the invention is better understood, the same consists in the novel construction, combination and'arrangement of parts hereinafter' more fully described, illustrated and claimed. j I

A preferred and practical embodiment of the invention is shown inthe accompanying drawings, in which I 7 Figure 1 is a perspective view of the present device. I

Figure 2 is a horizontal sectional View.

thereof. 7

Figure 3 is a cross sectional view taken at right angles to Figure 2. J

Figure 4 is a detail bottom plan viewv of the device. I

Figure 5 is a diagrammatic view showing the circuits involved.

Similar reference characters designate corresponding parts throughout the several figures of the drawings. e According to the embodiment of the 1n vent-ion shown in the accompanying drawings the same preferably includes a base 1 having achamber or compartment 2 open ing at the bottom side thereofand closed by an insulating cover 3, the sand cover being secured to the base in any sultable mantheaerial binding post of the set. E:

ner, as by'na'ils or tacks. The upper. side ofthe base 1 is providedwitha fhub' 4t hav ing the radial spokes. 5 for supporting a spider-web coil designatedgenerally ass and including the two inductance windings S and 8?. ""Between' the hub 4E and the top Of the base l'there is provided a concealed interiorly" threaded nut {6 whose threaded opening alines with the; registering openings rand; '7 respectively in the hub and the b'ase'fi The said 1nut '6 is adapted to alGCBlVG aheaded micrometer-screw 8 whose uppeu end is fitted with amanipulatingknob t). The lower headed end of-thescrew 8 is adapted to, bear against an insulation sheet 10 which overlies afcondenser designated generally as C andhousedin the chamber 2 The said condenser C preferably consists ofa plurality of elongated metal plates 11 of longitudin'ally arched formation arranged in alternate relation with the mica or equiv alent dielectric members 12. The metallic condenser plates 11 are provided'with the terminal end portions 13 whereby the ends lt'of the inductance winding S of the coil S maybe attached-thereto. 1

[The said'base'l also carries therewith the binding terminals 15 and 16 which connect with the primarywinding S of the spider .web c-oil'S, a dareano adapted to'connect respectively" with the lead-in wire from. the aerial andthe relatively short lead wire 'to As will be observed from the diagram in Figure 5, the present device includes a tunable circuit S C'suitably coupled by a coil S to the collector or pick-up circuit A of the receiving system. The tuned circuit S C consists of the fixed inductance S and a variable capacity C, having the micrometer screw adjustment, whilea second inductance S connected in the pick-up circuit is placed in inductance relation to the first mentioned inductance, both of which are wound on the same form or support 4*5.

The operation of the device is as follows:

The circuit S C is tuned to the fre quency of the interfering signal. The circuit of which coil S is a part,is tuned to a dif ferent frequency but is set into oscillation by the interfering slgnah'due to shock excitation'. The absorption circuit S C, extracts the interfering oscillations from the S circuit as fast as they are produced, thus effectively damping the undesirable oscillations n t e S. c rcu t. Th S -G circuit, be ng out of resonance with all other frequencies, has no-effect on the desired; signal.

In connection with the coil system S, including the inductance windings S ands? is Wound in the approved fashlon', being air spaced and employing a dry Wood frame. It consists of two inductanc'e's, one of 'Which (S is connected to the small bnass plate and mica condenser C, the other (S) being connected to-t-h'e pick-up system. 1T; his con- 1 denser C, being very small insize, has very low losses, the skin efiect in: particular bemg of little consequence, The outer plates are having the shortest possible leads, and the lowest losses. consistent withpi-acticab-ility of manufacture. 7 v connection With any type of radio receptor, the inductioncoil S being placed in the antenna circuit of the electro-static type of receiver, or inthe loop circuitof a magnetic type receptor. v V

The present construction also provides-as a distinctive feature, an efficient inductance coupled With a micro-metrically controlled capacity which are combined intov a practical unit that has a ide'rangeof utility iniradio reception. V e

' Without further description it is thought thatthe features and advantages of the invention will ,be readily apparent to those skilled'in the art,and ityvil'l of course be The device is also useful inv understood that changes in the form, proportion and: i'nin'or'deta-ils: of construction may be resorted to, Without departing from the spirit of the invention or'scope oi the v appended claims;

I c1ai n= An interference eliminator apparatus including an insulating 'base having achamber opening atits bottom side, a cover for the bottom sideso r' the b ase,--a

variable condenser consisting of arched spring metal plates ,andmi'ca dielectric mem bers alternately arranged and spaced apart, a spidereb, coil mounted on, top of the base to said base, a nufi'eleinent, concealed between the hub and the top of the base and having a threaded. opening registering with V corre- V sponding openings in the hub and base, a micrometer S rew engag ng the threaded for radio and, in uding al -11b por i ef XQdQQ IIL eLlY openingiof the-nut and having an exterior 7 manipulating knob vvhereby. the iscrew may ates p c apa t a i .m ii tedfon saidmsean including ahub portion fixed to bas'e a nut having a threaded open ng re lst ring with corresp-Qnding op nings in t e (unkind b s a ml rometer s rewf e gagi g 11511 threaded openingof the nut and'havi g an exterior man pulating; knc l fi her byfihe,

screw may be moved itf Q compress and release the plates ofthe:condensertheieby tg 'vary its capacity.

In testimony whereof lhereurito Ieifix.

signature.

' FRED WILLiAM 

